Using the techniquesof molecular biology, we wish to establish various strategies to detect, map and eventually diagnose specific mutations in the human genome. We choose to study the human globin genes as a model for this study due to the wealth of genetic data available onthe many different globin mutations. Specifically, we wish to: 1. detect the sickle cell point mutation by hybridization of oligonucleotides to genomic DNA (an extension of our previous project period), 2. map point mutations by digestion of heteroduplexes of control cloned DNAs and genomic DNA at the sites of polymorphism using Sl nuclease, 3. determine whether Sl nuclease can be used to create polymorphism mapes of defined regions of the genome (loci). This may lead to Sl fragment length polymorphisms (SFLP) suitable to establish a genetic linkage map, 4. study restriction fragment length polymorphism (RFLP) of the sickle cell Beta-globin gene using cloning techniques, 5. map specific genes to the chromosomal location by in situ hybridization using cloned DNA fragments. The studies proposed in this application will contribute to the long-term objective of a complete genetic map of the human genome. It will provide new, more sensitive techniques for the detection of point mutatons and for mapping polymorphisms using Sl nuclease. It is hoped that through a more detailed knowledge of the human genome, we will be able to diagnose genetic diseases sooner and perhaps have a better understanding of treatment procedures. In addition, the techniques of molecular biology are sensitive and accurate enough to allow prenatal diagnosis of genetic diseases for which the molecular basis or linkage pattern is known.